Sowing element for precision agricultural seeders and seeder including element of this kind

ABSTRACT

Sowing element for precision agricultural seeders comprising a device for selecting the seed, of the type which is formed of a perforated disc having opposing faces that are subject to a pressure differential and a pressurisation device associated with the disc for applying the pressure differential to the faces of the disc, the pressurisation device including a pressurisation bell combined with the disc so as to pneumatically couple thereto in order to guarantee said pressure differential, wherein the bell is rotatably idle with respect to the disc.

The present invention relates to a sowing element for precisionagricultural seeders and a seeder including an element of this kind.

The problem of precision when sowing is felt in the agricultural sectorsince the yield of the harvested product substantially depends on thedensity of plants with respect to the surface unit sown. The sowingdensity in turn depends on meticulously respecting the distance betweentwo adjacent seeds which are buried in the ground. This measure dependsboth on the precision design features of the seeder and on the sowingspeed. Of course, in order to achieve good profitability it is necessaryfor the sowing speed to be maximised, so as to allow the operator to sowan even greater number of hectares per hour.

The best results in maximising the sowing speed and sowing precision canbe achieved using pneumatic seeders that are provided with a perforateddisc distributor that is rotated by electric motors. This allows therotational speed of the selection disc and therefore the number of seedsdeposited per linear metre of the sowing bed to be accuratelycontrolled.

However, the seeding elements designed in this way have severaldisadvantages, some of which are due to the need to minimise thefriction inside the sowing element so as to not interfere withcontrolling the rotational speed of the electric motors which actuatethe selection discs. US2014/0182496A1 discloses a sowing elementcomprising a pneumatic device for selecting the seed in which a face ofthe disc is pressurised (positively or negatively with respect to theambient pressure) with respect to the other face by means of a bell thatis applied to the selection disc so as to jointly rotate therewith anddefines therewith a chamber in which there is established the negativepressure outside the aforementioned chamber that is required to adhere aseed at each hole of the disc on the opposite face to same.

This solution offers advantages in terms of pressurising the seedselection device but has quite a few disadvantages.

In fact, this design system makes replacing the selection discs everytime the sowing density has to be changed more complicated; for example,in order to change the type of seed used, the separating device has tobe dismounted and subsequently remounted in its position. The system forhooking the disc on the bell is necessarily produced along the externalcrown of the bell by means of screws. Removing the discs requires thescrews which fix the disc to the bell to be removed and therefore to berepositioned when applying the new disc. Moreover, a system fortemporarily locking the rotation of the bell needs to be provided inorder to allow the disc to be easily unhooked.

A further disadvantage stems from the fact that, using this structure,the motion is imparted to the disc by the bell and, for this reason, thebell is mounted on the fixed part of the box-shaped body of the seedselection device. In contrast, the chamber for containing the seed(drawing chamber) is made in the movable part or cover. As a result,every time work needs to be done on the disc, it is necessary for thechamber containing the seed and the tank that feeds said chamber bygravity to be completely emptied.

A further aspect relates to the positioning of the air aspiration tubeswhich connect each sowing element to the pneumatic vacuum generator. Ina situation of this kind, in fact, the positioning of said tubes cannotbe optimised. Other measures relate to the system for interrupting thevacuum on the face of the disc that is subjected to a vacuum, whichsystem is used to cause the seed to fall into the seed descent duct, andalso relate to the internal geometry of the chamber.

Nevertheless, there is the fact that if the bell is also onlytemporarily locked or decelerated, the correct rotation of the sowingdisc is not ensured.

Reference is also made to WO2017/079515 and EP2683231.

The technical problem addressed by the present invention is that ofdeveloping a sowing element for precision agricultural seeders which isstructurally and functionally designed to remedy all of thedisadvantages described with reference to the cited prior art.

This problem is solved according to the invention by means of a sowingelement produced in accordance with the accompanying claims.

By using a bell that is idly supported in the sowing element withrespect to the seed selection disc, it is possible to maintain andespecially to support the selection disc inside the sowing element in acompletely autonomous way with respect to the bell such that the sowingdisc is accessible and can be replaced without using measures other thansimply opening the element itself without any intervention on the bell.

Moreover, the rotation of the sowing disc is not negatively influencedby possible deceleration or locking of the bell, thereby ensuringgreater precision in sowing plants per surface unit.

The dragging effect between the bell and the sowing disc is in fact notessential, but is however ensured by the condition of contact betweenthe bell and the disc, owing to the friction of the respective contactsurfaces. The design of the bell and of the selection disc is in factmade simpler by adopting peripheral dragging of this kind caused byfriction between the disc and the bell.

The features and advantages of the invention will become clearer fromthe detailed description of a preferred embodiment thereof, shown by wayof non-restrictive example and with reference to the accompanyingdrawings, in which:

FIG. 1 is a front elevation of a sowing element for precisionagricultural seeders, which sowing element is produced according to theinvention;

FIG. 2 is an exploded perspective view of a detail of the element inFIG. 1;

FIG. 3 is an exploded perspective view of the same detail in FIG. 2,viewed from a different angle;

FIGS. 4 and 5 are a front elevation and sectional view along the lineV-V in FIG. 4, respectively, of the same detail;

FIGS. 6 and 7 are a front elevation and sectional view along the lineVI-VI in FIG. 6, respectively, of a component of the detail in thepreceding figures;

FIGS. 8 and 9 are sectional and perspective views, respectively, of adetail in FIG. 2;

FIGS. 10 and 11 are a front elevation and sectional view along the lineXI-XI in FIG. 10, respectively, of a component of the detail in thepreceding figures in a variant embodiment.

In the drawings, the reference numeral 1 indicates, as a whole, a sowingelement for precision agricultural seeders. A seeder of this kind is notdepicted as a whole but generally comprises, in a manner known per se,an element-holder bar to which a plurality of sowing elements 1 isfixed, the elements being spaced apart.

Each sowing element 1 comprises a frame 2, a parallelogrammicalarticulated mount 3 by means of which the frame 2 of the element 1 isconnected to the element-holder bar, a tank comprising a hopper 4 forcontaining the seed, one or more coulters 5, for example disc coulters,for opening a sowing furrow, a pair of wheels 6 for regulating thesowing depth and a furrow-covering device 7 for closing the furrowopened by the coulters 5 and thereby recovering the seed.

The reference numeral 10 indicates, as a whole, a device for selectingthe seed, which device is fed by gravity from the hopper 4 and isdesigned a distribute one seed at a time at a correct depth and spacingin the sowing furrow.

According to one preferred embodiment, the seed selection device 10comprises a box-shaped body 11 that is fixedly mounted on the frame 2and is provided with an opening that is removably closed by a cover 13.The box-shaped body and cover can be hinged to one another or, moresimply, connected by means of screws 14, the loosening of which allowsthe cover to be completely taken off the opening on which it rests.

A connector 15 is preferably made in the box-shaped body 11, with whichconnector the tank 4, an air vent 16 and a seed descent duct 17 engage.A selection disc 18 engages with the driving shaft 21 of an electricmotor 22 or other device, preferably by means of a polygonal coupling 19and relative hub 20, in order to drag the disc into rotation about theaxis thereof.

In one embodiment, a chamber 23 for drawing the seed is defined betweenthe bottom 12 of the box-shaped body 11 and the selection disc 18. Bymeans of a shutter 24 arranged downstream of the connector 15, it ispossible to regulate the flow of seeds falling from the hopper 4 intothe chamber 23 in order to divide said flow or optionally interrupt it.According to a further aspect, an inspection door 25 is provided,preferably in the lowest part of the chamber 23, so as to allow thechamber to be completely emptied if necessary.

The selection disc 18 is peripherally engaged by one or more crowns ofholes 26 that pass between the opposing faces 18 a, b thereof. In oneembodiment, the distance between the mean circumference on which theholes 26 lie and the maximum circumference of the chamber 23 is equal tothe radius of a large seed of between approximately 2 and 6 mm.

Defined as a vertical plane X that contains the axis of the seed descentduct and the plane of oscillation of the parallelogrammical articulatedmount 3, the plane at which the selection disc 18 lies, parallel to thefaces 18 a, b, is preferably inclined by an angle A of between 10° and20° with respect to the vertical plane X, a preferred value ofinclination being approximately 15°.

According to a preferred embodiment, the bottom 12 of the box-shapedbody 11 is inclined by an angle B of approximately 50°-60° (preferredvalue 56°) with respect to the plane at which the disc 18 lies and thebottom surface of the chamber 23 (the surface in which the door 25 ismade) in such a way that the seed always tends to descend towards theselection disc 18 and that stagnation of seeds at the bottom of thechamber 23 is avoided.

A pressurisation bell 30 is idly supported on the cover 13 around a hub31, which is preferably hollow. In one embodiment, the hub 31 is part ofa pressurised duct of a pressurisation device associated with theselection disc 18 for applying a pressure differential between the twofaces 18 a, b.

The pressurisation device includes the pressurisation bell 30 and apressurised distribution duct 32 which preferably extends from the hub31 through a raised radial rib structure 36 on the cover 13. In oneembodiment, the duct 32 is partially integrated in the cover 13 andpartially extends in the box-shaped body 11, the two parts being joinedby means of a male/female coupling connector 32 a, b or a connector ofanother type, for example a flanged connector. According to a preferredembodiment, the part of the duct 32 that is integral with the box-shapedbody 11 terminates in a first shell manifold 33 formed on the body 11.The rib structure 36 is preferably shaped so as to be raised on thecover 13 for a predominant part of the extent thereof.

According to a further aspect, the duct 32 for the part made in the ribstructure 36 is integrated into the cover and is closed in turn by acover 33 b that can be removed for inspection and cleaning. It is notedthat the raised position of the rib structure 36 with respect to thecover forms a handle which allows the cover 13 to be gripped andmanoeuvred from and towards the body 11 using one hand.

In one embodiment, the pressurisation bell 30 is idly supported on thehub 31 by means of a washer 34 and a bearing 35 in an opposite positionwith respect to the selection disc 18, and is held on the hub 31 by aring 46.

The bell 30 has a perimeter crown 37 that is raised by a disc-shapedbase 37 b and is in sliding peripheral contact with the selection disc18 when (and only when) the cover 13 is closed on the opening of thebox-shaped body 11, pulling said disc 18 towards the bell 30 as aconsequence of the vacuum established between the disc and the bell as aresult of the aspiration of air through the pressurisation device. Theperimeter crown is sized such that it contacts the surface 18 b of thedisc along a surface which lies outside the crown of holes 26. Thistherefore results in the bell being dragged into rotation together withthe disc, which can occur preferably by means of friction between thebell and the disc and more precisely by means of friction between theperimeter margin of the disc and the perimeter crown 37 of the bell.Alternatively, the connection between the bell 30 and the disc 18 can beprovided by a mechanical coupling between the bell and the disc, forexample by means of one or more teeth that can be mutually coupled whenthe perimeter crown 37 of the bell couples to the surface of the disc 18when the cover 13 is closed on the corresponding opening of thebox-shaped body. When the cover 13 is removed from the opening of thebox-shaped body 11, the bell 30 and the disc 18 are mutually decoupledwhile remaining rotatably supported on the cover 13 and on thestationary part of the box-shaped body, respectively.

In one embodiment, a vacuum-breaker block 38 is mounted inside the bell30, so as to be stationary, by means of a flat spring 39. The block 38can be formed in two or more adjacent independent portions, each beingstressed against the surface 18 b of the disc so as to interrupt thepressure differential at the holes 26 which pass in front thereof overthe entire transit course controlled by the block 38. This causes theseed detained at the holes 26 to fall, when passing in front of theblock 38, into the sowing duct. In a variant embodiment of theinvention, depicted in FIGS. 10 and 11, the air vent 16 is replaced by asecond manifold 40 that is connected, by means of a tube 41, to a device42 for filtering the pressurised air, or to a remote aspiration positionwhere the air available for the pressurisation system is relativelyclean and not perturbed. Since in this example the bell 30 is negativelypressurised, or the first manifold is connected to the aspiration inletof a ventilation system (not shown), it is sufficient for the secondmanifold to be maintained at ambient pressure. However, the bell 30 canbe positively pressurised, and in this case the second manifold 40 canbe connected to the delivery inlet of the aforementioned ventilationsystem.

The sowing element 1 operates as follows.

The seeds contained in the hopper 4 are fed by gravity into the chamber23 for drawing the seed at a flow regulated by means of the shutter 24.The seeds lying in the drawing chamber are drawn as a result of thepressure differential established between the surfaces 18 a, b at theholes 26, therefore adhering to the surface of the disc 18.

Said disc is rotated at a speed that is controlled and proportional tothe forward speed of the seeder on the ground by means of the motor 21,bringing the aspirated seeds through the holes 26 against the surface 18a to be passed firstly in front of a separating device 43 and then infront of the mouth of the seed descent duct, where they are released bythe disc as a result of the interruption of the pressure differentialcaused by the vacuum-breaker block 38 and are routed to the seed descentduct 17 in order to be deposited in the sowing furrow.

The pressure differential required for the seed selection is ensured atthe surface 18 b of the bell 30 which, being free to rotate (idle) aboutthe axis thereof, is dragged by the friction from the selection disc 18by means of the contact produced with the perimeter crown 37. It isnoted that the pressure differential between the two faces of the disc18 causes said disc to adhere to the perimeter crown 37, facilitatingthe dragging thereof. It is also noted that this design does not requirethe use of sliding washers on the disc and that, even if the bell isaccidentally locked, the sowing regularity is not compromised. It isalso noted that the washers that are active on the bell rest on regionsthat have a reduced diameter with respect to the diameter of the disc 18or of the perimeter crown 37, such that the resistant torques producedare minimal and therefore do not affect the torque of the motor that isavailable at the shaft 21.

If access to the disc 18 is desired in order to replace it, it issufficient for the cover 13 to be removed by releasing the screwsclosing said cover. The cover can be grasped using one hand by means ofthe handle provided by the rib structure 36 that houses the duct 32. Thecover is not connected to any tube of the pressurisation system andtherefore is not prevented from being manoeuvred.

In so doing, the invention solves the problem posed while providingseveral further advantages.

Among these, there are the possibility of avoiding connecting tubes orother to the cover which can therefore be manoeuvred without anyinterference, the possibility of using air drawn through a secondmanifold which allows the pneumatic flow to be purified by means offiltration, decantation, cyclonic separation or other means, and thepossibility, in this last case, of also mounting the second manifold onthe fixed part of the seed selection device, therefore leaving the coverunhindered.

Further advantages result from the inclined positioning with respect tothe vertical plane of the disc and of the wall of the chamber fordrawing the seed, and from the fact that removing the bell in order toreplace the disc does not interfere with the positioning and/or theregulation of possible seed separation devices that are applied to thebox-shaped body in order to remove from the holes of the disc possibleduplicate seeds that are adhered to the disc at the holes.

1. Sowing element for precision agricultural seeders comprising a devicefor selecting the seed that includes: a box-shaped body that is fixedlymounted on a frame of the sowing element and provided with an openingthat is removably closed by a cover, a perforated disc that is rotatablysupported in the box-shaped body and has opposing faces which can besubject to a pressure differential, a pressurisation device associatedwith said disc for applying said pressure differential to said faces,said pressurisation device including a pressurisation bell combined withsaid disc so as to pneumatically couple thereto in order to guaranteesaid pressure differential, characterised in that said bell is idlyrotatably supported on said cover, and is coupled to the disc fordragging when the cover is closed on the opening of the box-shaped body.2. Sowing element according to claim 1, comprising a motorisation systemfor rotating the disc with respect to the box-shaped body, and whereinthe motorisation system is kinematically connected to the disc and notto the bell, said bell being dragged into rotation by the disc. 3.Sowing element according to claim 2, wherein the bell is dragged byfriction between the bell and the disc.
 4. Sowing element according toclaim 2, wherein the bell is dragged by mechanical coupling between thebell and the disc.
 5. Sowing element according to one or more of thepreceding claims, wherein said disc is supported on said box-shaped bodyand defines therewith a chamber for drawing the seed, said bell beingsupported on said cover and being removable therewith from saidbox-shaped body and said disc.
 6. Sowing element according to one ormore of the preceding claims, wherein a manifold of said pressurisationdevice is provided on said box-shaped body.
 7. Sowing element accordingto one or more of the preceding claims, wherein the cover is equippedwith a raised rib structure which forms a handle for manoeuvring saidcover from and towards the fixed part of the box-shaped body.
 8. Sowingelement according to claim 7, wherein said rib structure forms apressurised distribution duct between said manifold and said bell. 9.Sowing element according to claim 8, wherein said rib structure isequipped with a cover that can be opened.
 10. Sowing element accordingto one or more of the preceding claims, wherein the bell has a perimetercollar, which is in sliding contact with one of the surfaces of thedisc, along one surface external to the crown of holes of said disc. 11.Sowing element according to one or more of the preceding claims, whereina second manifold is provided on said seed selection device, whichmanifold is pneumatically connected to an air vent of saidpressurisation device.
 12. Sowing element according to claim 11, whereinthe second manifold is pneumatically connected to a filtration system orto a remote aspiration system.
 13. Sowing element according to eitherclaim 11 or claim 12, wherein the second manifold is provided on saidbox-shaped body.
 14. Precision agricultural seeder including anelement-holder bar to which a plurality of sowing elements according toone or more of the preceding claims is fixed, the elements being spacedapart.